My initial tests of the newest dejavu-fonts-ttf.scm, and gtk2.scm were done on a system that had fontconfig.tcz installed, so they are not wholly valid.
TC v4.7.2 booted from CD-ROM (cloud mode) and apps downloaded as required.
dejavu-fonts-ttf.scm+opera9.scm=Dejavu not available
dejavu-fonts-ttf.scm+opera9.scm+gtk2.scm=Dejavu not available
...for now I can mention in the info file to install fontconfig.tcz to get full font access.
I'm not sure about this. It seems to negate the value of using the SCM. If fontconfig.tcz is required in order to use the fonts, one might as well also use dejavu-fonts-ttf.tcz and thereby have system-wide access to the fonts. Or have I missed your point?